Gas water heater



GAS WATER HEATER Filed July 11. 1928 2 Sheets-Sheet 1 INVENTOR. T O W Harm ATTORNEYS.

Oct. 18, o w HAHN GAS WATER HEATER Filed July 11. 1928 2 Sheets-Sheet 2 Patentecloct. 18, 1932 V UNITED STATES o'r'ro w. mum, or an: imaixcie00,-oanr l'onznn on warm Application fledluly 11, me. semi Ho. 201,040.

7 This invention relates to gas water heaters of the so called instantaneous typeand has for its ob'ects improved construction in such heaters w ereby a greater eflicieucy is secured over other heaters now obtainable, and whereby sweating or condensing of water from the hot gases of combustion is entirely overcome. Other objects and advantages will appear in the following description. 4 10 In the drawings accompanying this apphcation Fig. 1 is a front elevation of my heater shown with portion of the casing broken away to more clearly reveal the pi es within. Fig. 2 is a side elevation of ig. 1 with parts broken away, to show the internalstructure. V v

Fi 3 is a cross sectional view of a portion of F1 1 as seen from the line 3-3 thereof, and i 4 is a cross sectional view of a por- F'Fig. 2 as seen from the line 4-'4 20 tion thereof.

In further detail the heater comprises an outer sheet metal casing 1 preferably of oblong cross section with rounded corners, and

25 it is surmounted by a conical portion 2 telescopin looselyat 3 into the lower portion. Space y arranged within this casing is a tubular sheet metal shell 4 preferably of copper and ofslightly tapering form with its small end terminating at 5 from where it extends verticall at 4' a ort distance and is surmounted y a freely fitting conical hood 6 in turn surmounted by a stack 7 passing easily through a neck 8 formed on the outer conical portion 2 of the casing.

At its lower end the inner shell 4 is supported on a horizontally extending plate 9 which closes off the lower end of the space 10 between the casing and shell.

A row of relatively small apertures 11. are formed around the lower end of the shell to open communication from within the space 10 and at the top of conical member 6 a similar row of apertures 12 opens communi cation from the space 10 to the stack.

Extendin over the area at the open lower end of she 4 is a gas burner comprising a series of horizontally arranged pipes13, crossing, secured to and opening into a large pipe 50 14 delivering gas to the burner.

not strike another flame.

These small pipes are arranged parallel to one another, are closed at the ends and are drilled with rows of holes 15 along the upper .sides and the apertures alternately extending It is also a feature of this heater that the flames preferably be yellow flames, as such have been found by careful test to give better results in this particular heater construction than a Bunsen flame.

The outer casing'l extends downwardly below the burner, and within the casing under the burner is a curved plate 16 secured to vertical walls17 pivoted to the casin at 18 so that it may be swung downward an away from the burner like a tray, while within the confines of the curved plate 16- is a second curved late 19 provided with end walls 20 adjusta ly clamped to the end walls of plate 16 by means ofthumb screws 21 working in slots 22.

' The lower front wall of the casing is cut away to form an elongated a-ir admission opening 23 and overhanging this is a down wardlycurved plate orr hgod 24 preferably provided with end wells2f,' and a screen at 26 where all the air foriwghurner enters.

The burner being difliiTult-of access for lighting I provide a pilot; lighter consisting of a tube 27 pivotally suspended at its upper end from the casing at 28 and curved on an are from the pivotal point at its lower end so as to swing through small openings made in the casing and end wall 17 of the curved plate, so that it may be swung out of the casing to light gas agits end and then swung back into the casin to thereby ignite the burner. A handle 29 is provided'onthe pilot for swinging it as described and the weight of this handle overbalances it so that normally the pilot is within the casing.

Any suitable slip joint not shown connects the pivoted end of the pilot to the gas supply.

So much for the general housing and burner construction, and the remaining features consisting of the water coil arrangement with respect to this housing will now be described.

The water supply pipe enters near the bottom of the casing about on a level with the top of the gas burner and branching from pipe 30 are two copper tubes 31-31 which make one turn around the lower end of the shell 4 in a substantially horizontal direction, then continue in spaced relation at a considerable angle in several turns around the shell, then at somewhat reduced angularity about the upper straight portion of the shell in the manner indicated in the figures and the two pipes pass respectively into the end of the shell and back and forth in several layers across the ascending heat column in the manner indicated in Fig. 3 of the drawings and wherein the pipes respectively enter at A, B, make a horizontal return bend outside of the shell to return at A, B, then a downward return outside of the shell to runs A B, then a horizontal return to A, B, then a downward return to A, B, followed by a horizontal return to runs A, B to emerge from the shell three layers of pipe below the entering layer and the emerging pipes are then joined to a common outlet pipe AB.

The tubes are preferably brazed or soldered to the shell 4 so as to be in metallic contact for ready absorption of heat from the shell.

The three layers of pipe passing through the upper or vertical portion 4' of the shell form a detachable unit with it so that by loosening the coupling nuts from the outlet pipe and the spirally ascending tubes the upper section with its layers of pipe may be lifted off of the conical section 4of the shell, telescopically engaging meeting edges of the shell members being provided for that purpose, and as indicated in Fig. 3.

Embracing the two upper layers of pipe within the heat area are sheet metal (preferably copper) fins or heat absorbing and transmitting plates 32. These fins are punched with necks to form spacing collars on the pipes, and. in such a manner that the fins or plates slant at an angle to the vertical, half of them in one direction and the other half in the p'pposite direction as indicated in Fig. 1 so as to better intercept the rising heat for its absorption and direct the products of combustion centrally toward the stack.

The fins it should be observed are in metallic contact with the two upper layers of pipe only and are continuous in embracing all the pipes of these two layers.

The importance of this may not be apparcut at first, but careful tests have shown that the arrangement efl'ects entire freedom from sweat or condensed moisture dripping from the pipes, whereas separate fins'spaced over allof the pipes did not overcome the nuisance of condensation and dripping.

The reason for the freedom from sweating of the adopted construction would appear to be due to the fact that plates on the upper layers of pipe where the water is not so warm so that water beads will drip from theupper row of pipes right through to the bottom of the heater.

The whole arrangement of heater and pip; ing would therefore appear to be in accordance with a principle not heretofore used, i. e. of delivering heat from a burner to the water coils, first gently from an easily heated thin metal shell in metallic contact with the pipes, and gradually increasing the heat as the pipes ascend around the shell, then when passing the pipes through the hot gases insuring that they will be heated above the condensation point, and finally extending the pipes downward toward the source of heat to emerge from a shell confining the prodnets of combustion at its point of restriction where the gases have the greatest velocity and greatest heat to deliver to the outgoing pipes, and I believe the above construction to be something new in a sweatless heater, and in tests made with large output of hot water and great volume of flame sufiicient to give practically instantaneous effect no sweating whatever takes place notwithstanding the fact that the stack gases feel wet to the hand.

Other factors contributing to high efiiciency in this heater is the use of a yellow flame which seems to have greater radiating capacity than a blue flame, also that a small portion of the heated gases pass through openings 11 and form an ascending current of heat through the shell space 4 to pass out at 12 to the stack thus overcoming heat radiation losses from the water coils to the outer casing 1 and in fact contributing to their heating.

The outer casing 1 may of course be covered inside or outside with a thermal insulator if desired, though with the construction shown as much as thermal efiiciency has been shown in heating water with the apparatus.

As a safety against explosions the conical portions 2 and 6 are loose at their juncture to their supporting members so that they can of the upper row to the condensing point rise bodil and the swinging air deflector an 16 be ow the burner is held up with a riction catch at 33 so that it will readily release, thus in case of accidentally filling the device with gas and 1i hting it the shell will not be destroyed but t e force will be spent both up and down.

Havlng thus described my invention I claim:

1. A water heater comprising a casing, a sheet metal vertically disposed tubular inner shell spacedly mountedinsaid casing and 0 en top and bottom water pipe coils mounted on the outside of the inner shell, a gas burner at the bottom of the inner shell arranged for its hot gases to pass upward through the shell, and means provided for causing a relatively small amount of the hot gases to pass upward from the burner through the space between the shell and casing.

2. A water heater comprising a casing, a sheet metal vertically disposed tubular inner shell spacedly mounted in said casing and open top and bottom, water pipe coils mounted on the outside of the inner shell, a gas burner at the bottom of the inner shell arranged for its hot gases to pass upward through the shell and means provided for causing a relatively small amount of the hot gases to pass upward from the burner through the space between the shell and casing, and a stack above said casing arranged to receive the hot gases from both within and without said shell.

3. A water heater comprising a casing, a sheel metal vertically disposed tubular shell spacedl mounted in said casing and open at top an bottom, water pipe coils mounted on the inner shell, a gas burner at the bottom of the inner shell, said pipe coils being passed across the upper end of the inner shell space and provided with anfiularly disposed heatabsorbing fins genera y converging toward the center of the heater when viewed in elevation, and a stack positioned above to receive hot gases converged by said fins.

4. A water heater comprising a casin a sheet metal vertically dis osed tubular s ell spacedly mounted in sai casing and open at top and bottom and provided with laterally extending passages at its lower margin water pipe coils mounted on the outside 0 the inner shell, a gas burner at the bottom of the inner shell, a plate closing the space at the bottom between the shell and easing at a point below said laterall extending passages, and stack means at t e top of the cusing arranged and adapted to receive hot gases from within and without said shell, said passages being of a size to permit a relatively small amount of gases to pass to the space between the shells.

5. A water heater comprising. a casin a sheet metal vertically disposed tubular e11 spacedly mounted in said casing and open top and bottom, water pipe coils mounted on the inner shell, a burner at the bottom of the inner shell extending horizontally under said ipe coils, and a curved late under said urner arranged to guide air for combustion from one side u ward into said shell, and a second curved plate spacedly mounted with in the confines of the first 'curved plate to better control the flow of air.

6. In a water heater a tubular shell, a burner at the bottom of the shell, and a water tube provided with a plurality of runs extendin horizontally across the hot gas space of sai shell, heat transmitting fins on said runs, and additional runs of the tube below the first mentioned runs free from fins conveying the heated water from the heater for use.

7. A water heater comprising a sheet metal vertically disposed tubular shell open at the top, a burner at the bottom thereof arranged to discharge its hot gases therethrough a pipe coil around the outside of said shell ma in a turn substantially around the lower end 0 the shell, thence angularly and upwardly extending turns, then passing through the rising gas space in the open top of the shell in downwardly extending coils and out.

OTTO W. HAHN. 

